Multi-nodal thermostat control system

ABSTRACT

An Electronically-Controlled Register vent (ECRV) that can be easily installed by a homeowner or general handyman is disclosed. The ECRV can be used to convert a non-zoned HVAC system into a zoned system. The ECRV can also be used in connection with a conventional zoned HVAC system to provide additional control and additional zones not provided by the conventional zoned HVAC system. In one embodiment, the ECRV is configured have a size and form-factor that conforms to a standard manually-controlled register vent. In one embodiment, a zone thermostat is configured to provide thermostat information to the ECRV. In one embodiment, the zone thermostat communicates with a central monitoring system that coordinates operation of the heating and cooling zones.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.14/182,759, filed Feb. 18, 2014, which is a continuation of U.S.application Ser. No. 13/269,155, filed Oct. 7, 2011, which is acontinuation of U.S. application Ser. No. 11/669,066, filed Jan. 30,2007, now U.S. Pat. No. 8,033,479, issued Oct. 11, 2011, which is acontinuation-in-part application of U.S. application Ser. No.10/959,362, filed Oct. 6, 2004, now U.S. Pat. No. 7,168,627, issued Jan.30, 2007, which are hereby incorporated by reference in their entiretyfor all purposes.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a system and method for directingheating and cooling air from an air handler to various zones in a homeor commercial structure.

2. Description of the Related Art

Most traditional home heating and cooling systems have onecentrally-located thermostat that controls the temperature of the entirehouse. The thermostat turns the Heating, Ventilating, andAir-Conditioner (HVAC) system on or off for the entire house. The onlyway the occupants can control the amount of HVAC air to each room is tomanually open and close the register vents throughout the house.

Zoned HVAC systems are common in commercial structures, and zonedsystems have been making inroads into the home market. In a zonedsystem, sensors in each room or group of rooms, or zones, monitor thetemperature. The sensors can detect where and when heated or cooled airis needed. The sensors send information to a central controller thatactivates the zoning system, adjusting motorized dampers in the ductworkand sending conditioned air only to the zone in which it is needed. Azoned system adapts to changing conditions in one area without affectingother areas. For example, many two-story houses are zoned by floor.Because heat rises, the second floor usually requires more cooling inthe summer and less heating in the winter than the first floor. Anon-zoned system cannot completely accommodate this seasonal variation.Zoning, however, can reduce the wide variations in temperature betweenfloors by supplying heating or cooling only to the space that needs it.

A zoned system allows more control over the indoor environment becausethe occupants can decide which areas to heat or cool and when. With azoned system, the occupants can program each specific zone to be activeor inactive depending on their needs. For example, the occupants can setthe bedrooms to be inactive during the day while the kitchen and livingareas are active.

A properly zoned system can be up to 30 percent more efficient than anon-zoned system. A zoned system supplies warm or cool air only to thoseareas that require it. Thus, less energy is wasted heating and coolingspaces that are not being used.

In addition, a zoned system can sometimes allow the installation ofsmaller capacity equipment without compromising comfort. This reducesenergy consumption by reducing wasted capacity.

Unfortunately, the equipment currently used in a zoned system isrelatively expensive. Moreover, installing a zoned HVAC system, orretrofitting an existing system, is far beyond the capabilities of mosthomeowners. Unless the homeowner has specialized training, it isnecessary to hire a specially-trained professional HVAC technician toconfigure and install the system. This makes zoned HVAC systemsexpensive to purchase and install. The cost of installation is such thateven though the zoned system is more efficient, the payback period onsuch systems is many years. Such expense has severely limited the growthof zoned HVAC systems in the general home market.

BRIEF DESCRIPTION OF THE INVENTION

The system and method disclosed herein solves these and other problemsby providing an Electronically-Controlled Register vent (ECRV) that canbe easily installed by a homeowner or general handyman. The ECRV can beused to convert a non-zoned HVAC system into a zoned system. The ECRVcan also be used in connection with a conventional zoned HVAC system toprovide additional control and additional zones not provided by theconventional zoned HVAC system. In one embodiment, the ECRV isconfigured have a size and form-factor that conforms to a standardmanually-controlled register vent. The ECRV can be installed in place ofa conventional manually-controlled register vent—often without the useof tools.

In one embodiment, the ECRV is a self-contained zoned system unit thatincludes a register vent, a power supply, a thermostat, and a motor toopen and close the register vent. To create a zoned HVAC system, thehomeowner can simply remove the existing register vents in one or morerooms and replace the register vents with the ECRVs. The occupants canset the thermostat on the EVCR to control the temperature of the area orroom containing the ECRV. In one embodiment, the ECRV includes a displaythat shows the programmed setpoint temperature. In one embodiment, theECRV includes a display that shows the current setpoint temperature. Inone embodiment, the ECRV includes a remote control interface to allowthe occupants to control the ECRV by using a remote control. In oneembodiment, the remote control includes a display that shows theprogrammed temperature and the current temperature. In one embodiment,the remote control shows the battery status of the ECRV.

In one embodiment, the EVCR includes a pressure sensor to measure thepressure of the air in the ventilation duct that supplies air to theEVCR. In one embodiment, the EVCR opens the register vent if the airpressure in the duct exceeds a specified value. In one embodiment, thepressure sensor is configured as a differential pressure sensor thatmeasures the difference between the pressure in the duct and thepressure in the room.

In one embodiment, the ECRV is powered by an internal battery. Abattery-low indicator on the ECRV informs the homeowner when the batteryneeds replacement. In one embodiment, one or more solar cells areprovided to recharge the batteries when light is available. In oneembodiment, the register vent include a fan to draw additional air fromthe supply duct in order to compensate for undersized vents or zonesthat need additional heating or cooling air.

In one embodiment, one or more ECRVs in a zone communicate with a zonethermostat. The zone thermostat measures the temperature of the zone forall of the ECRVs that control the zone. In one embodiment, the ECRVs andthe zone thermostat communicate by wireless communication methods, suchas, for example, infrared communication, radio-frequency communication,ultrasonic communication, etc. In one embodiment, the ECRVs and the zonethermostat communicate by direct wire connections. In one embodiment,the ECRVs and the zone thermostat communicate using powerlinecommunication.

In one embodiment, one or more zone thermostats communicate with acentral controller.

In one embodiment, the EVCR and/or the zoned thermostat includes anoccupant sensor, such as, for example, an infrared sensor, motionsensor, ultrasonic sensor, etc. The occupants can program the EVCR orthe zoned thermostat to bring the zone to different temperatures whenthe zone is occupied and when the zone is empty. In one embodiment, theoccupants can program the EVCR or the zoned thermostat to bring the zoneto different temperatures depending on the time of day, the time ofyear, the type of room (e.g. bedroom, kitchen, etc.), and/or whether theroom is occupied or empty. In one embodiment, various EVCRs and/or zonedthermostats thought a composite zone (e.g., a group of zones such as anentire house, an entire floor, an entire wing, etc.) intercommunicateand change the temperature setpoints according to whether the compositezone is empty or occupied.

In one embodiment, the home occupants can provide a priority schedulefor the zones based on whether the zones are occupied, the time of day,the time of year, etc. Thus, for example, if zone corresponds to abedroom and zone corresponds to a living room, zone can be given arelatively lower priority during the day and a relatively higherpriority during the night. As a second example, if zone corresponds to afirst floor, and zone corresponds to a second floor, then zone can begiven a higher priority in summer (since upper floors tend to be harderto cool) and a lower priority in winter (since lower floors tend to beharder to heat). In one embodiment, the occupants can specify a weightedpriority between the various zones.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a home with zoned heating and cooling.

FIG. 2 shows one example of a conventional manually-controlled registervent.

FIG. 3A is a front view of one embodiment of anelectronically-controlled register vent.

FIG. 3B is a rear view of the electronically-controlled register ventshown in FIG. 3A.

FIG. 4 is a block diagram of a self-contained ECRV.

FIG. 5 is a block diagram of a self-contained ECRV with a remotecontrol.

FIG. 6 is a block diagram of a locally-controlled zoned heating andcooling system wherein a zone thermostat controls one or more ECRVs.

FIG. 7A is a block diagram of a centrally-controlled zoned heating andcooling system wherein the central control system communicates with oneor more zone thermostats and one or more ECRVs independently of the HVACsystem.

FIG. 7B is a block diagram of a centrally-controlled zoned heating andcooling system wherein the central control system communicates with oneor more zone thermostats and the zone thermostats communicate with oneor more ECRVs.

FIG. 8 is a block diagram of a centrally-controlled zoned heating andcooling system wherein a central control system communicates with one ormore zone thermostats and one or more ECRVs and controls the HVACsystem.

FIG. 9 is a block diagram of an efficiency-monitoringcentrally-controlled zoned heating and cooling system wherein a centralcontrol system communicates with one or more zone thermostats and one ormore ECRVs and controls and monitors the HVAC system.

FIG. 10 is a block diagram of an ECRV for use in connection with thesystems shown in FIGS. 6-9.

FIG. 11 is a block diagram of a basic zone thermostat for use inconnection with the systems shown in FIGS. 6-9.

FIG. 12 is a block diagram of a zone thermostat with remote control foruse in connection with the systems shown in FIGS. 6-9.

FIG. 13 shows one embodiment of a central monitoring system.

FIG. 14 is a flowchart showing one embodiment of an instruction loop foran ECRV or zone thermostat.

FIG. 15 is a flowchart showing one embodiment of an instruction andsensor data loop for an ECRV or zone thermostat.

FIG. 16 is a flowchart showing one embodiment of an instruction andsensor data reporting loop for an ECRV or zone thermostat.

FIG. 17 shows an ECRV configured to be used in connection with aconventional T-bar ceiling system found in many commercial structures.

FIG. 18 shows an ECRV configured to use a scrolling curtain to controlairflow as an alternative to the vanes shown in FIGS. 2 and 3.

FIG. 19 is a block diagram of a control algorithm for controlling theregister vents.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a home 100 with zoned heating and cooling. In the home 100,an HVAC system provides heating and cooling air to a system of ducts.Sensors 101-105 monitor the temperature in various areas (zones) of thehouse. A zone can be a room, a floor, a group of rooms, etc. The sensors101-105 detect where and when heating or cooling air is needed.Information from the sensors 101-105 is used to control actuators thatadjust the flow of air to the various zones. The zoned system adapts tochanging conditions in one area without affecting other areas. Forexample, many two-story houses are zoned by floor. Because heat rises,the second floor usually requires more cooling in the summer and lessheating in the winter than the first floor. A non-zoned system cannotcompletely accommodate this seasonal variation. Zoning, however, canreduce the wide variations in temperature between floors by supplyingheating or cooling only to the space that needs it.

FIG. 2 shows one example of a conventional manually-controlled registervent 200. The register 200 includes one or more vanes 201 that can beopened or closed to adjust the amount of air that flows through theregister 200. Diverters 202 direct the air in a desired direction (ordirections). The vanes 201 are typically provided to a mechanicalmechanism so that the occupants can manipulate the vanes 201 to controlthe amount of air that flows out of the register 200. In some registers,the diverters 202 are fixed. In some registers, the diverters 202 aremoveable to allow the occupants some control over the direction of theairflow out of the vent. Registers such as the register 200 are foundthroughout homes that have a central HVAC system that provides heatingand cooling air. Typically, relatively small rooms such as bedrooms andbathrooms will have one or two such register vents of varying sizes.Larger rooms, such as living rooms, family rooms, etc., may have morethan two such registers. The occupants of a home can control the flow ofair through each of the vents by manually adjusting the vanes 201. Whenthe register vent is located on the floor, or relatively low on thewall, such adjustment is usually not particularly difficult (unless themechanism that controls the vanes 201 is bent or rusted). However,adjustment of the vanes 201 can be very difficult when the register vent200 is located so high on the wall that it cannot be easily reached.

FIG. 3 shows one embodiment of an Electronically-Controlled RegisterVent (ECRV) 300. The ECRV 300 can be used to implement a zoned heatingand cooling system. The ECRV 300 can also be used as a remotely controlregister vent in places where the vent is located so high on the wallthat is cannot be easily reached. The ECRV 300 is configured as areplacement for the vent 200. This greatly simplifies the task ofretrofitting a home by replacing one or more of the register vents 200with the ECRVs 300. In one embodiment, shown in FIG. 3, the ECRV 300 isconfigured to fit into approximately the same size duct opening as theconventional register vent 200. In one embodiment, the ECRV 300 isconfigured to fit over the duct opening used by the conventionalregister vent 200. In one embodiment, the ECRV 300 is configured to fitover the conventional register 200, thereby allowing the register 200 tobe left in place. A control panel 301 provides one or more visualdisplays and, optionally, one or more user controls. A housing 302 isprovided to house an actuator to control the vanes 201. In oneembodiment, the housing 302 can also be used to house electronics,batteries, etc.

FIG. 4 is a block diagram of a self-contained ECRV 400, which is oneembodiment of the ECRV 300 shown in FIGS. 3A and 3B and the ECRV shownin FIG. 18. In the ECRV 400, a temperature sensor 406 and a temperaturesensor 416 are provided to a controller 401. The controller 401 controlsan actuator system 409. In one embodiment, the actuator 409 providesposition feedback to the controller 401. In one embodiment, thecontroller 401 reports actuator position to a central control systemand/or zone thermostat. The actuator system 409 provided mechanicalmovements to control the airflow through the vent. In one embodiment,the actuator system 409 includes an actuator provided to the vanes 201or other air-flow devices to control the amount of air that flowsthrough the ECRV 400 (e.g., the amount of air that flows from the ductinto the room). In one embodiment, an actuator system includes anactuator provided to one or more of the diverters 202 to control thedirection of the airflow. The controller 401 also controls a visualdisplay 403 and an optional fan 402. A user input device 408 is providedto allow the user to set the desired room temperature. An optionalsensor 407 is provided to the controller 401. In one embodiment, thesensor 407 includes an air pressure and/or airflow sensor. In oneembodiment, the sensor 407 includes a humidity sensor. A power source404 provides power to the controller 401, the fan 402, the display 403,the temperature sensors 406, 416, the sensor 407, and the user inputdevice 408 as needed. In one embodiment, the controller 401 controls theamount of power provided to the fan 402, the display 403, the sensor406, the sensor 416, the sensor 407, and the user input device 408. Inone embodiment, an optional auxiliary power source 405 is also providedto provide additional power. The auxiliary power source is asupplementary source of electrical power, such as, for example, abattery, a solar cell, an airflow (e.g., wind-powered) generator, thefan 402 acting as a generator, a nuclear-based electrical generator, afuel cell, a thermocouple, etc.

In one embodiment, the power source 404 is based on a non-rechargeablebattery and the auxiliary power source 405 includes a solar cell and arechargeable battery. The controller 401 draws power from the auxiliarypower source when possible to conserve power in the power source 404.When the auxiliary power source 405 is unable to provide sufficientpower, then the controller 401 also draws power from the power source404.

In an alternative embodiment, the power source 404 is configured as arechargeable battery and the auxiliary power source 405 is configured asa solar cell that recharges the power source 404.

In one embodiment, the display 403 includes a flashing indicator (e.g.,a flashing LED or LCD) when the available power from the power sources404 and/or 405 drops below a threshold level.

The home occupants use the user input device 408 to set a desiredtemperature for the vicinity of the ECRV 400. The display 403 shows thesetpoint temperature. In one embodiment, the display 403 also shows thecurrent room temperature. The temperature sensor 406 measures thetemperature of the air in the room, and the temperature sensor 416measures the temperature of the air in the duct. If the room temperatureis above the setpoint temperature, and the duct air temperature is belowthe room temperature, then the controller 401 causes the actuator 409 toopen the vent. If the room temperature is below the setpointtemperature, and the duct air temperature is above the room temperature,then the controller 401 causes the actuator 409 to open the vent.Otherwise, the controller 401 causes the actuator 409 to close the vent.In other words, if the room temperature is above or below the setpointtemperature and the temperature of the air in the duct will tend todrive the room temperature towards the setpoint temperature, then thecontroller 401 opens the vent to allow air into the room. By contrast,if the room temperature is above or below the setpoint temperature andthe temperature of the air in the duct will not tend to drive the roomtemperature towards the setpoint temperature, then the controller 401closes the vent.

In one embodiment, the controller 401 is configured to provide a fewdegrees of hysteresis (often referred to as a thermostat deadband)around the setpoint temperature in order to avoid wasting power byexcessive opening and closing of the vent.

In one embodiment, the controller 401 turns on the fan 402 to pulladditional air from the duct. In one embodiment, the fan 402 is usedwhen the room temperature is relatively far from the setpointtemperature in order to speed the movement of the room temperaturetowards the setpoint temperature. In one embodiment, the fan 402 is usedwhen the room temperature is changing relatively slowly in response tothe open vent. In one embodiment, the fan 402 is used when the roomtemperature is moving away from the setpoint and the vent is fully open.The controller 401 does not turn on or run the fan 402 unless there issufficient power available from the power sources 404, 405. In oneembodiment, the controller 401 measures the power level of the powersources 404, 405 before turning on the fan 402, and periodically (orcontinually) when the fan is on.

In one embodiment, the controller 401 also does not turn on the fan 402unless it senses that there is airflow in the duct (indicating that theHVAC air-handler fan is blowing air into the duct). In one embodiment,the sensor 407 includes an airflow sensor. In one embodiment, thecontroller 401 uses the fan 402 as an airflow sensor by measuring (orsensing) voltage generated by the fan 402 rotating in response to airflowing from the duct through the fan and causing the fan to act as agenerator. In one embodiment, the controller 401 periodically stop thefan and checks for airflow from the duct.

In one embodiment, the sensor 406 includes a pressure sensor configuredto measure the air pressure in the duct. In one embodiment, the sensor406 includes a differential pressure sensor configured to measure thepressure difference between the air in the duct and the air outside theECRV (e.g., the air in the room). Excessive air pressure in the duct isan indication that too many vents may be closed (thereby creating toomuch back pressure in the duct and reducing airflow through the HVACsystem). In one embodiment, the controller 401 opens the vent whenexcess pressure is sensed.

The controller 401 conserves power by turning off elements of the ECRV400 that are not in use. The controller 401 monitors power availablefrom the power sources 404, 405. When available power drops below alow-power threshold value, the controls the actuator 409 to an openposition, activates a visual indicator using the display 403, and entersa low-power mode. In the low power mode, the controller 401 monitors thepower sources 404, 405 but the controller does not provide zone controlfunctions (e.g., the controller does not close the actuator 409). Whenthe controller senses that sufficient power has been restored (e.g.,through recharging of one or more of the power sources 404, 405, thenthe controller 401 resumes normal operation.

Whistling and other noises related to turbulence can be a problem whenair of a certain velocity passes through an orifice or opening In oneembodiment, the controller 401 uses the physical parameters of the ventto estimate when airflow through the vent may cause undesirable noisessuch as whistling and the like. The controller 401 can then avoidrelatively small vent openings (e.g., smaller partial openings) of thevent that produce unacceptable noises. Since whistling and other suchnoises are dependent on how much the vent is open and the air pressureacross the vent, the openings that would cause unacceptable noises mayvary depending on which other vents in the zone system are open orclosed. By using data from the pressure/airflow sensor 407 and thedimensions of the vent, the controller 401 can calculate which settingsare likely to produce whistling and other noises at any given time andthus, vary the allowed settings accordingly. In one embodiment, amicrophone or other acoustic sensor is provided to the controller 401such that the controller can sense acoustic noise created by air flowingthrough the vent. In one embodiment, the controller evaluates theamplitude of the noise detected by the acoustic sensor to determinewhether unacceptable noise is being produced. In one embodiment, thecontroller 401 performs spectral properties of the noise (e.g., by usingFourier transform, wavelet transform, etc.) to determine whetherunacceptable noise is being produced. The use of a booster fan inconnection with the ECRV increases the possibility of noise. Thecontroller 401 can also use noise estimates or measurements to helpdetermine if a booster fan and/or the allowable speed for the fan.

If too many vents are closed off, then the remaining vents, even whencompletely open, may cause unacceptable noises. In one embodiment, thecontroller 401 informs the zone thermostats and/or control systemsdescribed below that a vent is producing noise. The zone thermostatand/or control system can then open other vents to reduce the pressure,instruct the blower fan to operate at a lower speed, turn off or reducethe speed of booster fans in the ductwork, etc.

FIG. 5 is a block diagram of a self-contained ECRV 500 with a remotecontrol interface 501. The ECRV 500 includes the power sources 404, 405,the controller 401, the fan 402, the display 403, the temperaturesensors 406, 416, the sensor 407, and the user input device 408. Theremote control interface 501 is provided to the controller 401, to allowthe controller 401 to communicate with a remote control 502. Thecontroller 502 sends wireless signals to the remote control interface501 using wireless communication such as, for example, infraredcommunication, ultrasonic communication, and/or radio-frequencycommunication.

In one embodiment, the communication is one-way, from the remote control502 to the controller 401. The remote control 502 can be used to set thetemperature setpoint, to instruct the controller 401 to open or closethe vent (either partially or fully), and/or to turn on the fan. In oneembodiment, the communication between the remote control 502 and thecontroller 401 is two-way communication. Two-way communication allowsthe controller 401 to send information for display on the remote control502, such as, for example, the current room temperature, the powerstatus of the power sources 404, 405, diagnostic information, etc.

The ECRV 400 described in connection with FIG. 4, and the ECRV 500described in connection with FIG. 5 are configured to operate asself-contained devices in a relatively stand-alone mode. If two ECRVs400, 500 are placed in the same room or zone, the ECRVs 400, 500 willnot necessarily operate in unison. FIG. 6 is a block diagram of alocally-controlled zoned heating and cooling system 600 wherein a zonethermostat 601 monitors the temperature of a zone 608. ECRVs 602, 603are configured to communicate with the zone thermostat 601. Oneembodiment of the ECRVs 620-603 is shown, for example, in connectionwith FIG. 10. In one embodiment, the zone thermostat 601 sends controlcommands to the ECRVs 602-603 to cause the ECRVs 602-603 to open orclose. In one embodiment, the zone thermostat 601 sends temperatureinformation to the ECRVs 602-603 and the ECRVs 602-603 determine whetherto open or close based on the temperature information received from thezone thermostat 601. In one embodiment, the zone thermostat 601 sendsinformation regarding the current zone temperature and the setpointtemperature to the ECRVs 602-603.

In one embodiment, the ECRV 602 communicates with the ECRV 603 in orderto improve the robustness of the communication in the system 600. Thus,for example, if the ECRV 602 is unable to communicate with the zonethermostat 601 but is able to communicate with the ECRV 603, then theECRV 603 can act as a router between the ECRV 602 and the zonethermostat 601. In one embodiment, the ECRV 602 and the ECRV 603communicate to arbitrate opening and closing of their respective vents.

The system 600 shown in FIG. 6 provides local control of a zone 608. Anynumber of independent zones can be controlled by replicating the system600. FIG. 7A is a block diagram of a centrally-controlled zoned heatingand cooling system wherein a central control system 710 communicateswith one or more zone thermostats 707 708 and one or more ECRVs 702-705.In the system 700, the zone thermostat 707 measures the temperature of azone 711, and the ECRVs 702, 703 regulate air to the zone 711. The zonethermostat 708 measures the temperature of a zone 712, and the ECRVs704, 705 regulate air to the zone 711. A central thermostat 720 controlsthe HVAC system 720.

FIG. 7B is a block diagram of a centrally-controlled zoned heating andcooling system 750 that is similar to the system 700 shown in FIG. 7A.In FIG. 7B, the central system 710 communicates with the zonethermostats 707, 708, the zone thermostat 707 communicates with theECRVs 702, 703, the zone thermostat 708 communicates with the ECRVs 704,705, and the central system 710 communicates with the ECRVs 706, 707. Inthe system 750, the ECRVs 702-705 are in zones that are associated withthe respective zone thermostat 707, 708 that controls the respectiveECRVs 702-705. The ECRVs 706, 707 are not associated with any particularzone thermostat and are controlled directly by the central system 710.One of ordinary skill in the art will recognize that the communicationtopology shown in FIG. 7B can also be used in connection with the systemshown in FIGS. 8 and 9.

The central system 710 controls and coordinates the operation of thezones 711 and 712, but the system 710 does not control the HVAC system721. In one embodiment, the central system 710 operates independently ofthe thermostat 720. In one embodiment, the thermostat 720 is provided tothe central system 710 so that the central system 710 knows when thethermostat is calling for heating, cooling, or fan.

The central system 710 coordinates and prioritizes the operation of theECRVs 702-705. In one embodiment, the home occupants and provide apriority schedule for the zones 711, 712 based on whether the zones areoccupied, the time of day, the time of year, etc. Thus, for example, ifzone 711 corresponds to a bedroom and zone 712 corresponds to a livingroom, zone 711 can be given a relatively lower priority during the dayand a relatively higher priority during the night. As a second example,if zone 711 corresponds to a first floor, and zone 712 corresponds to asecond floor, then zone 712 can be given a higher priority in summer(since upper floors tend to be harder to cool) and a lower priority inwinter (since lower floors tend to be harder to heat). In oneembodiment, the occupants can specify a weighted priority between thevarious zones.

Closing too many vents at one time is often a problem for central HVACsystems as it reduces airflow through the HVAC system, and thus reducesefficiency. The central system 710 can coordinate how many vents areclosed (or partially closed) and thus, ensure that enough vents are opento maintain proper airflow through the system. The central system 710can also manage airflow through the home such that upper floors receiverelatively more cooling air and lower floors receive relatively moreheating air.

FIG. 8 is a block diagram of a centrally-controlled zoned heating andcooling system 800. The system 800 is similar to the system 700 andincludes the zone thermostats 707, 708 to monitor the zones 711, 712,respectively, and the ECRVs 702-705. The zone thermostats 707, 708and/or the ECRVs 702-705 communicate with a central controller 810. Inthe system 800, the thermostat 720 is provided to the central system 810and the central system 810 controls the HVAC system 721 directly.

The controller 810 provides similar functionality as the controller 710.However, since the controller 810 also controls the operation of theHVAC system 721, the controller 810 is better able to call for heatingand cooling as needed to maintain the desired temperature of the zones711, 712. If all, or substantially, all of the home is served by thezone thermostats and ECRVs, then the central thermostat 720 can beeliminated.

In some circumstances, depending on the return air paths in the house,the controller 810 can turn on the HVAC fan (without heating or cooling)to move air from zones that are too hot to zones that are too cool (orvice versa) without calling for heating or cooling. The controller 810can also provide for efficient use of the HVAC system by calling forheating and cooling as needed, and delivering the heating and cooling tothe proper zones in the proper amounts. If the HVAC system 721 providesmultiple operating modes (e.g., high-speed, low-speed, etc.), then thecontroller 810 can operate the HVAC system 721 in the most efficientmode that provides the amount of heating or cooling needed.

FIG. 9 is a block diagram of an efficiency-monitoringcentrally-controlled zoned heating and cooling system 900. The system900 is similar to the system 800. In the system 900 the controller 810is replaced by an efficiency-monitoring controller 910 that isconfigured to receive sensor data (e.g., system operating temperatures,etc.) from the HVAC system 721 to monitor the efficiency of the HVACsystem 721.

FIG. 10 is a block diagram of an ECRV 1000 for use in connection withthe systems shown in FIGS. 6-9. The ECRV 1000 includes the power sources404, 405, the controller 401, the fan 402, the display 403, and,optionally the temperature sensors 416 and the sensor 407, and the userinput device 408. A communication system 1081 is provided to thecontroller 401. The remote control interface 501 is provided to thecontroller 401, to allow the controller 401 to communicate with a remotecontrol 502. The controller 502 sends wireless signals to the remotecontrol interface 501 using wireless communication such as, for example,infrared communication, ultrasonic communication, and/or radio-frequencycommunication.

The communication system 1081 is configured to communicate with the zonethermometer and, optionally, with the central controllers 710, 810, 910.In one embodiment, the communication system 1081 is configured tocommunicate using wireless communication such as, for example, infraredcommunication, radio communication, or ultrasonic communication.

FIG. 11 is a block diagram of a basic zone thermostat 1100 for use inconnection with the systems shown in FIGS. 6-9. In the zone thermostat1100, a temperature sensor 1102 is provided to a controller 1101. Userinput controls 1103 are also provided to the controller 1101 to allowthe user to specify a setpoint temperature. A visual display 1110 isprovided to the controller 1101. The controller 1101 uses the visualdisplay 1110 to show the current temperature, setpoint temperature,power status, etc. The communication system 1181 is also provided to thecontroller 1101. The power source 404 and, optionally, 405 are providedto provide power for the controller 1100, the controls 1101, the sensor1103, the communication system 1181, and the visual display 1110.

In systems where a central controller 710, 810, 910 is used, thecommunication method used by the zone thermostat 1100 to communicatewith the ECRV 1000 need not be the same method used by the zonethermostat 1100 to communicate with the central controller 710, 810,910. Thus, in one embodiment, the communication system 1181 isconfigured to provide one type of communication (e g, infrared, radio,ultrasonic) with the central controller, and a different type ofcommunication with the ECRV 1000.

In one embodiment, the zone thermostat is battery powered. In oneembodiment, the zone thermostat is configured into a standard lightswitch and receives electrical power from the light switch circuit.

FIG. 12 is a block diagram of a zone thermostat 1200 with remote controlfor use in connection with the systems shown in FIGS. 6-9. Thethermostat 1200 is similar to the thermostat 1100 and includes, thetemperature sensor 1102, the input controls 1103, the visual display1110, the communication system 1181, and the power sources 404, 405. Inthe zone thermostat 1200, the remote control interface 501 is providedto the controller 1101.

In one embodiment, an occupant sensor 1201 is provided to the controller1101. The occupant sensor 1201, such as, for example, an infraredsensor, motion sensor, ultrasonic sensor, etc. senses when the zone isoccupied. The occupants can program the zone thermostat 1201 to bringthe zone to different temperatures when the zone is occupied and whenthe zone is empty. In one embodiment, the occupants can program thezoned thermostat 1201 to bring the zone to different temperaturesdepending on the time of day, the time of year, the type of room (e.g.bedroom, kitchen, etc.), and/or whether the room is occupied or empty.In one embodiment, a group of zones are combined into a composite zone(e.g., a group of zones such as an entire house, an entire floor, anentire wing, etc.) and the central system 710, 810, 910 changes thetemperature setpoints of the various zones according to whether thecomposite zone is empty or occupied.

FIG. 13 shows one embodiment of a central monitoring station console1300 for accessing the functions represented by the blocks 710, 810, 910in FIGS. 7, 8, 9, respectively. The station 1300 includes a display 1301and a keypad 1302. The occupants can specify zone temperature settings,priorities, and thermostat deadbands using the central system 1300and/or the zone thermostats. In one embodiment, the console 1300 isimplemented as a hardware device. In one embodiment, the console 1300 isimplemented in software as a computer display, such as, for example, ona personal computer. In one embodiment, the zone control functions ofthe blocks 710, 810, 910 are provided by a computer program running on acontrol system processor, and the control system processor interfaceswith personal computer to provide the console 1300 on the personalcomputer. In one embodiment, the zone control functions of the blocks710, 810, 910 are provided by a computer program running on a controlsystem processor provided to a hardware console 1300. In one embodiment,the occupants can use the Internet, telephone, cellular telephone,pager, etc. to remotely access the central system to control thetemperature, priority, etc. of one or more zones.

FIG. 14 is a flowchart showing one embodiment of an instruction loopprocess 1400 for an ECRV or zone thermostat. The process 1400 begins ata power-up block 1401. After power up, the process proceeds to aninitialization block 1402. After initialization, the process advances toa “listen” block 1403 wherein the ECRV or zone thermostat listens forone or more instructions. If a decision block 1404 determines that aninstruction has been received, then the process advances to a “performinstruction” block 1405, otherwise the process returns to the listenblock 1403.

For an ECRV, the instructions can include: open vent, close vent, openvent to a specified partially-open position, report sensor data (e.g.,airflow, temperature, etc.), report status (e.g., battery status, ventposition, etc.), and the like. For a zone thermostat, the instructionscan include: report temperature sensor data, report temperature rate ofchange, report setpoint, report status, etc. In systems where thecentral system communicates with the ECRVs through a zone thermostat,the instructions can also include: report number of ECRVs, report ECRVdata (e.g., temperature, airflow, etc.), report ECRV vent position,change ECRV vent position, etc.

In one embodiment, the listen block 1403 consumes relatively littlepower, thereby allowing the ECRV or zone thermostat to stay in the loopcorresponding to the listen block 1403 and conditional branch 1404 forextended periods of time.

Although the listen block 1403 can be implemented to use relativelylittle power, a sleep block can be implemented to use even less power.FIG. 15 is a flowchart showing one embodiment of an instruction andsensor data loop process 1500 for an ECRV or zone thermostat. Theprocess 1500 begins at a power-up block 1501. After power up, theprocess proceeds to an initialization block 1502. After initialization,the process advances to a “sleep” block 1503 wherein the ECRV or zonethermostat sleeps for a specified period of time. When the sleep periodexpires, the process advances to a wakeup block 1504 and then to adecision 1505. In the decision block 1505, if a fault is detected, thena transmit fault block 1506 is executed. The process then advances to asensor block 1507 where sensor readings are taken. After taking sensorreadings, the process advances to a listen-for-instructions block 1508.If an instruction has been received, then the process advances to a“perform instruction” block 1510; otherwise, the process returns to thesleep block 1503.

FIG. 16 is a flowchart showing one embodiment of an instruction andsensor data reporting loop process 1600 for an ECRV or zone thermostat.The process 1600 begins at a power-up block 1601. After power up, theprocess proceeds to an initialization block 1602. After initialization,the process advances to a check fault block 1603. If a fault is detectedthen a decision block 1604 advances the process to a transmit faultblock 1605; otherwise, the process advances to a sensor block 1606 wheresensor readings are taken. The data values from one or more sensors areevaluated, and if the sensor data is outside a specified range, or if atimeout period has occurred, then the process advances to a transmitdata block 1608; otherwise, the process advances to a sleep block 1609.After transmitting in the transmit fault block 1605 or the transmitsensor data block 1608, the process advances to a listen block 1610where the ECRV or zone thermostat listens for instructions. If aninstruction is received, then a decision block advances the process to aperform instruction block 1612; otherwise, the process advances to thesleep block 1609. After executing the perform instruction block 1612,the process transmits an “instruction complete message” and returns tothe listen block 1610.

The process flows shown in FIGS. 14-16 show different levels ofinteraction between devices and different levels of power conservationin the ECRV and/or zone thermostat. One of ordinary skill in the artwill recognize that the ECRV and zone thermostat are configured toreceive sensor data and user inputs, report the sensor data and userinputs to other devices in the zone control system, and respond toinstructions from other devices in the zone control system. Thus theprocess flows shown in FIGS. 14-16 are provided for illustrativepurposes and not by way of limitation. Other data reporting andinstruction processing loops will be apparent to those of ordinary skillin the art by using the disclosure herein.

In one embodiment, the ECRV and/or zone thermostat “sleep,” betweensensor readings. In one embodiment, the central system 710 sends out a“wake up” signal. When an ECRV or zone thermostat receives a wake upsignal, it takes one or more sensor readings, encodes it into a digitalsignal, and transmits the sensor data along with an identification code.

In one embodiment, the ECRV is bi-directional and configured to receiveinstructions from the central system. Thus, for example, the centralsystem can instruct the ECRV to: perform additional measurements; go toa standby mode; wake up; report battery status; change wake-up interval;run self-diagnostics and report results; etc.

In one embodiment, the ECRV provides two wake-up modes, a first wake-upmode for taking measurements (and reporting such measurements if deemednecessary), and a second wake-up mode for listening for commands fromthe central system. The two wake-up modes, or combinations thereof, canoccur at different intervals.

In one embodiment, the ECRVs use spread-spectrum techniques tocommunicate with the zone thermostats and/or the central system. In oneembodiment, the ECRVs use frequency-hopping spread-spectrum. In oneembodiment, each ECRV has an Identification code (ID) and the ECRVsattaches its ID to outgoing communication packets. In one embodiment,when receiving wireless data, each ECRV ignores data that is addressedto other ECRVs.

In one embodiment, the ECRV provides bi-directional communication and isconfigured to receive data and/or instructions from the central system.Thus, for example, the central system can instruct the ECRV to performadditional measurements, to go to a standby mode, to wake up, to reportbattery status, to change wake-up interval, to run self-diagnostics andreport results, etc. In one embodiment, the ECRV reports its generalhealth and status on a regular basis (e.g., results of self-diagnostics,battery health, etc.).

In one embodiment, the ECRV use spread-spectrum techniques tocommunicate with the central system. In one embodiment, the ECRV usesfrequency-hopping spread-spectrum. In one embodiment, the ECRV has anaddress or identification (ID) code that distinguishes the ECRV from theother ECRVs. The ECRV attaches its ID to outgoing communication packetsso that transmissions from the ECRV can be identified by the centralsystem. The central system attaches the ID of the ECRV to data and/orinstructions that are transmitted to the ECRV. In one embodiment, theECRV ignores data and/or instructions that are addressed to other ECRVs.

In one embodiment, the ECRVs, zone thermostats, central system, etc.,communicate on a 900 MHz frequency band. This band provides relativelygood transmission through walls and other obstacles normally found inand around a building structure. In one embodiment, the ECRVs and zonethermostats communicate with the central system on bands above and/orbelow the 900 MHz band. In one embodiment, the ECRVs and zonethermostats listen to a radio frequency channel before transmitting onthat channel or before beginning transmission. If the channel is in use,(e.g., by another device such as another central system, a cordlesstelephone, etc.) then the ECRVs and/or zone thermostats change to adifferent channel. In one embodiment, the sensor, central systemcoordinates frequency hopping by listening to radio frequency channelsfor interference and using an algorithm to select a next channel fortransmission that avoids the interference. In one embodiment, the ECRVand/or zone thermostat transmits data until it receives anacknowledgement from the central system that the message has beenreceived.

Frequency-hopping wireless systems offer the advantage of avoiding otherinterfering signals and avoiding collisions. Moreover, there areregulatory advantages given to systems that do not transmit continuouslyat one frequency. Channel-hopping transmitters change frequencies aftera period of continuous transmission, or when interference isencountered. These systems may have higher transmit power and relaxedlimitations on in-band spurs.

In one embodiment, the controller 401 reads the sensors 406, 407, 416 atregular periodic intervals. In one embodiment, the controller 401 readsthe sensors 406, 407, 416 at random intervals. In one embodiment, thecontroller 401 reads the sensors 406, 407, 416 in response to a wake-upsignal from the central system. In one embodiment, the controller 401sleeps between sensor readings.

In one embodiment, the ECRV transmits sensor data until ahandshaking-type acknowledgement is received. Thus, rather than sleep ifno instructions or acknowledgements are received after transmission(e.g., after the instruction block 1510, 1405, 1612 and/or the transmitblocks 1605, 1608) the ECRV retransmits its data and waits for anacknowledgement. The ECRV continues to transmit data and wait for anacknowledgement until an acknowledgement is received. In one embodiment,the ECRV accepts an acknowledgement from a zone thermometer and it thenbecomes the responsibility of the zone thermometer to make sure that thedata is forwarded to the central system. The two-way communicationability of the ECRV and zone thermometer provides the capability for thecentral system to control the operation of the ECRV and/or zonethermometer and also provides the capability for robust handshaking-typecommunication between the ECRV, the zone thermometer, and the centralsystem.

In one embodiment of the system 600 shown in FIG. 6, the ECRVs 602, 603send duct temperature data to the zone thermostat 601. The zonethermostat 601 compares the duct temperature to the room temperature andthe setpoint temperature and makes a determination as to whether theECRVs 602, 603 should be open or closed. The zone thermostat 601 thensends commands to the ECRVs 602, 603 to open or close the vents. In oneembodiment, the zone thermostat 601 displays the vent position on thevisual display 1110.

In one embodiment of the system 600 shown in FIG. 6, the zone thermostat601 sends setpoint information and current room temperature informationto the ECRVs 602, 603. The ECRVs 602, 603 compare the duct temperatureto the room temperature and the setpoint temperature and makes adetermination as to whether to open or close the vents. In oneembodiment, the ECRVs 602, 603 send information to the zone thermostat601 regarding the relative position of the vents (e.g., open, closed,partially open, etc.).

In the systems 700, 750, 800, 900 (the centralized systems) the zonethermostats 707, 708 send room temperature and setpoint temperatureinformation to the central system. In one embodiment, the zonethermostats 707, 708 also send temperature slope (e.g., temperature rateof rise or fall) information to the central system. In the systems wherethe thermostat 720 is provided to the central system or where thecentral system controls the HVAC system, the central system knowswhether the HVAC system is providing heating or cooling; otherwise, thecentral system used duct temperature information provide by the ECRVs702-705 to determine whether the HVAC system is heating or cooling. Inone embodiment, ECRVs send duct temperature information to the centralsystem. In one embodiment, the central system queries the ECRVs bysending instructions to one or more of the ECRVs 702-705 instructing theECRV to transmit its duct temperature.

The central system determines how much to open or close ECRVs 702-705according to the available heating and cooling capacity of the HVACsystem and according to the priority of the zones and the differencebetween the desired temperature and actual temperature of each zone. Inone embodiment, the occupants use the zone thermostat 707 to set thesetpoint and priority of the zone 711, the zone thermostat 708 to setthe setpoint and priority of the zone 712, etc. In one embodiment, theoccupants use the central system console 1300 to set the setpoint andpriority of each zone, and the zone thermostats to override (either on apermanent or temporary basis) the central settings. In one embodiment,the central console 1300 displays the current temperature, setpointtemperature, temperature slope, and priority of each zone.

In one embodiment, the central system allocates HVAC air to each zoneaccording to the priority of the zone and the temperature of the zonerelative to the setpoint temperature of the zone. Thus, for example, inone embodiment, the central system provides relatively more HVAC air torelatively higher priority zones that are not at their temperaturesetpoint than to lower priority zones or zones that are at or relativelynear their setpoint temperature. In one embodiment, the central systemavoids closing or partially closing too many vents in order to avoidreducing airflow in the duct below a desired minimum value.

In one embodiment, the central system monitors a temperature rate ofrise (or fall) in each zone and sends commands to adjust the amount eachECRV 702-705 is open to bring higher priority zones to a desiredtemperature without allowing lower-priority zones to stray too far formtheir respective setpoint temperature.

In one embodiment, the central system uses predictive modeling tocalculate an amount of vent opening for each of the ECRVs 702-705 toreduce the number of times the vents are opened and closed and therebyreduce power usage by the actuators 409. In one embodiment, the centralsystem uses a neural network to calculate a desired vent opening foreach of the ECRVs 702-705. In one embodiment, various operatingparameters such as the capacity of the central HVAC system, the volumeof the house, etc., are programmed into the central system for use incalculating vent openings and closings. In one embodiment, the centralsystem is adaptive and is configured to learn operating characteristicsof the HVAC system and the ability of the HVAC system to control thetemperature of the various zones as the ECRVs 702-705 are opened andclosed. In an adaptive learning system, as the central system controlsthe ECRVs to achieve the desired temperature over a period of time, thecentral system learns which ECRVs need to be opened, and by how much, toachieve a desired level of heating and cooling for each zone. The use ofsuch an adaptive central system is convenient because the installer isnot required to program HVAC operating parameters into the centralsystem. In one embodiment, the central system provides warnings when theHVAC system appears to be operating abnormally, such as, for example,when the temperature of one or more zones does not change as expected(e.g., because the HVAC system is not operating properly, a window ordoor is open, etc.).

In one embodiment, the adaptation and learning capability of the centralsystem uses different adaptation results (e.g., different coefficients)based on whether the HVAC system is heating or cooling, the outsidetemperature, a change in the setpoint temperature or priority of thezones, etc. Thus, in one embodiment, the central system uses a first setof adaptation coefficients when the HVAC system is cooling, and a secondset of adaptation coefficients when the HVAC system is heating. In oneembodiment, the adaptation is based on a predictive model. In oneembodiment, the adaptation is based on a neural network.

FIG. 17 shows an ECRV 1700 configured to be used in connection with aconventional T-bar ceiling system found in many commercial structures.In the ECRV 1700, an actuator 1701 (as one embodiment of the actuator409) is provided to a damper 1702. The damper 1702 is provided to adiffuser 1703 that is configured to mount in a conventional T-barceiling system. The ECRV 1700 can be connected to a zoned thermostat orcentral system by wireless or wired communication.

In one embodiment, the sensors 407 in the ECRVs include airflow and/orair velocity sensors. Data from the sensors 407 are transmitted by theECRV to the central system. The central system uses the airflow and/orair velocity measurements to determine the relative amount of airthrough each ECRV. Thus, for example, by using airflow/velocitymeasurements, the central system can adapt to the relatively lowerairflow of smaller ECRVs and ECRVs that are situated on the duct furtherfrom the HVAC blower than ECRVs which are located closer to the blower(the closer ECRVs tend to receive more airflow).

In one embodiment, the sensors 407 include humidity sensors. In oneembodiment, the zone thermostat 1100 includes a zone humidity sensorprovided to the controller 1101. The zone control system (e.g., thecentral system, the zone thermostat, and/or ECRV) uses humidityinformation from the humidity sensors to calculate zone comfort valuesand to adjust the temperature setpoint according to a comfort value.Thus, for example, in one embodiment during a summer cooling season, thezone control system lowers the zone temperature setpoint during periodsof relative high humidity, and raises the zone setpoint during periodsof relatively low humidity. In one embodiment, the zone thermostatallows the occupants to specify a comfort setting based on temperatureand humidity. In one embodiment, the zone control system controls theHVAC system to add or remove humidity from the heating/cooling air.

FIG. 18 shows a register vent 1800 configured to use a scrolling curtain1801 to control airflow as an alternative to the vanes shown in FIGS. 2and 3. An actuator 1802 (one embodiment of the actuator 409) is providedto the curtain 1801 to move the curtain 1801 across the register tocontrol the size of a register airflow opening In one embodiment, thecurtain 1801 is guided and held in position by a track 1803.

In one embodiment, the actuator 1802 is a rotational actuator and thescrolling curtain 1801 is rolled around the actuator 1802, and theregister vent 1800 is open and rigid enough to be pushed into the ventopening by the actuator 1802 when the actuator 1802 rotates to unrollthe curtain 1801.

In one embodiment, the actuator 1802 is a rotational actuator and thescrolling curtain 1801 is rolled around the actuator 1802, and theregister vent 1800 is open and rigid enough to be pushed into the ventopening by the actuator 1802 when the actuator 1802 rotates to unrollthe curtain 1801. In one embodiment, the actuator 1802 is configured toFIG. 19 is a block diagram of a control algorithm 1900 for controllingthe register vents. For purposes of explanation, and not by way oflimitation, the algorithm 1900 is described herein as running on thecentral system. However, one of ordinary skill in the art will recognizethat the algorithm 1900 can be run by the central system, by the zonethermostat, by the ECRV, or the algorithm 1900 can be distributed amongthe central system, the zone thermostat, and the ECRV. In the algorithm1900, in a block 1901 of the algorithm 1900, the setpoint temperaturesfrom one or more zone thermostats are provided to a calculation block1902. The calculation block 1902 calculates the register vent settings(e.g., how much to open or close each register vent) according to thezone temperature, the zone priority, the available heating and coolingair, the previous register vent settings, etc. as described above. Inone embodiment, the block 1902 uses a predictive model as describedabove. In one embodiment, the block 1902 calculates the register ventsettings for each zone independently (e.g., without regard tointeractions between zones). In one embodiment, the block 1902calculates the register vent settings for each zone in a coupled-zonemanner that includes interactions between zones. In one embodiment, thecalculation block 1902 calculates new vent openings by taking intoaccount the current vent openings and in a manner configured to minimizethe power consumed by opening and closing the register vents.

Register vent settings from the block 1902 are provided to each of theregister vent actuators in a block 1903, wherein the register vents aremoved to new opening positions as desired (and, optionally, one or moreof the fans 402 are turned on to pull additional air from desiredducts). After setting the new vent openings in the block 1903, theprocess advances to a block 1904 where new zone temperatures areobtained from the zone thermostats (the new zone temperatures beingresponsive to the new register vent settings made in block 1903). Thenew zone temperatures are provided to an adaptation input of the block1902 to be used in adapting a predictive model used by the block 1902.The new zone temperatures also provided to a temperature input of theblock 1902 to be used in calculating new register vent settings.

As described above, in one embodiment, the algorithm used in thecalculation block 1902 is configured to predict the ECRV opening neededto bring each zone to the desired temperature based on the currenttemperature, the available heating and cooling, the amount of airavailable through each ECRV, etc. The calculating block uses theprediction model to attempt to calculate the ECRV openings needed forrelatively long periods of time in order to reduce the power consumed inunnecessarily by opening and closing the register vents. In oneembodiment, the ECRVs are battery powered, and thus reducing themovement of the register vents extends the life of the batteries. In oneembodiment, the block 1902 uses a predictive model that learns thecharacteristics of the HVAC system and the various zones and thus themodel prediction tends to improve over time.

In one embodiment, the zone thermostats report zone temperatures to thecentral system and/or the ECRVs at regular intervals. In one embodiment,the zone thermostats report zone temperatures to the central systemand/or the ECRVs after the zone temperature has changed by a specifiedamount specified by a threshold value. In one embodiment, the zonethermostats report zone temperatures to the central system and/or theECRVs in response to a request instruction from the central system orECRV.

In one embodiment, the zone thermostats report setpoint temperatures andzone priority values to the central system or ECRVs whenever theoccupants change the setpoint temperatures or zone priority values usingthe user controls 1102. In one embodiment, the zone thermostats reportsetpoint temperatures and zone priority values to the central system orECRVs in response to a request instruction from the central system orECRVs.

In one embodiment, the occupants can choose the thermostat deadbandvalue (e.g., the hysteresis value) used by the calculation block 1902. Arelatively larger deadband value reduces the movement of the registervent at the expense of larger temperature variations in the zone.

In one embodiment, the ECRVs report sensor data (e.g., duct temperature,airflow, air velocity, power status, actuator position, etc.) to thecentral system and/or the zone thermostats at regular intervals. In oneembodiment, the ECRVs report sensor data to the central system and/orthe zone thermostats whenever the sensor data fails a threshold test(e.g., exceeds a threshold value, falls below a threshold value, fallsinside a threshold range, or falls outside a threshold range, etc.). Inone embodiment, the ECRVs report sensor data to the central systemand/or the zone thermostats in response to a request instruction fromthe central system or zone thermostat.

In one embodiment, the central system is shown in FIGS. 7-9 isimplemented in a distributed fashion in the zone thermostats 1100 and/orin the ECRVs. In the distributed system, the central system does notnecessarily exists as a distinct device, rather, the functions of thecentral system can be are distributed in the zone thermostats 1100and/or the ECRVs. Thus, in a distributed system, FIGS. 7-9 represent aconceptual/computational model of the system. For example, in adistributed system, each zone thermostat 100 knows its zone priority,and the zone thermostats 1100 in the distributed system negotiate toallocate the available heating/cooling air among the zones. In oneembodiment of a distributed system, one of the zone thermostat assumesthe role of a master thermostat that collects data from the other zonethermostats and implements the calculation block 1902. In one embodimentof a distributed system, the zone thermostats operate in a peer-to-peerfashion, and the calculation block 1902 is implemented in a distributedmanner across a plurality of zone thermostats and/or ECRVs.

In one embodiment, the fans 402 can be used as generators to providepower to recharge the power source 404 in the ECRV. However, using thefan 402 in such a manner restricts airflow through the ECRV. In oneembodiment, the controller 401 calculates a vent opening for the ECRV toproduce the desired amount of air through the ECRV while using the fanto generate power to recharge the power source 404 (thus, in suchcircumstance) the controller would open the vanes more than otherwisenecessary in order to compensate for the air resistance of the generatorfan 402. In one embodiment, in order to save power in the ECRV, ratherthan increase the vane opening, the controller 401 can use the fan as agenerator. The controller 401 can direct the power generated by the fan402 into one or both of the power sources 404, 405, or the controller401 can dump the excess power from the fan into a resistive load. In oneembodiment, the controller 401 makes decisions regarding vent openingversus fan usage. In one embodiment, the central system instructs thecontroller 401 when to use the vent opening and when to use the fan. Inone embodiment, the controller 401 and central system negotiate ventopening versus fan usage.

In one embodiment, the ECRV reports its power status to the centralsystem or zone thermostat. In one embodiment the central system or zonethermostat takes such power status into account when determining newECRV openings. Thus, for example, if there are first and second ECRVsserving one zone and the central system knows that the first ECRVs islow on power, the central system will use the second ECRV to modulatethe air into the zone. If the first ECRV is able to use the fan 402 orother airflow-based generator to generate electrical power, the centralsystem will instruct the second ECRV to a relatively closed position inand direct relatively more airflow through the first ECRV when directingair into the zone.

It will be evident to those skilled in the art that the invention is notlimited to the details of the foregoing illustrated embodiments and thatthe present invention may be embodied in other specific forms withoutdeparting from the spirit or essential attributed thereof; furthermore,various omissions, substitutions and changes may be made withoutdeparting from the spirit of the inventions. For example, althoughspecific embodiments are described in terms of the 900 MHz frequencyband, one of ordinary skill in the art will recognize that frequencybands above and below 900 MHz can be used as well. The wireless systemcan be configured to operate on one or more frequency bands, such as,for example, the HF band, the VHF band, the UHF band, the Microwaveband, the Millimeter wave band, etc. One of ordinary skill in the artwill further recognize that techniques other than spread spectrum canalso be used and/or can be used instead spread spectrum. The modulationuses is not limited to any particular modulation method, such thatmodulation scheme used can be, for example, frequency modulation, phasemodulation, amplitude modulation, combinations thereof, etc. The one ormore of the wireless communication systems described above can bereplaced by wired communication. The one or more of the wirelesscommunication systems described above can be replaced by powerlinenetworking communication. The foregoing description of the embodimentsis, therefore, to be considered in all respects as illustrative and notrestrictive, with the scope of the invention being delineated by theappended claims and their equivalents.

What is claimed is:
 1. A multi-nodal thermostat control system for astructure comprising: a central control system configured to control aheating, ventilation, and air conditioning (HVAC) system of thestructure; and a plurality of remote wireless sensor nodes to be locatedin a plurality of areas within the structure, each remote wirelesssensor node of the plurality of the remote wireless sensor nodescomprising: a temperature sensor for measuring a temperature in an areaof the plurality of areas within the structure in which the wirelesssensor node is located; an occupant sensor for sensing one or morepersons in the area of the plurality of areas within the structure inwhich the wireless sensor node is located; a wireless radio frequency(RF) communication module for bidirectional communication between thewireless sensor node and the central control system; a controller incommunication with the temperature sensor, the occupant sensor, and thewireless RF communication module, the controller being configured totransmit, via the wireless RF communication module, at least datareceived from the occupant sensor and the temperature sensor to thecentral control system; and a power source for powering the controller,the temperature sensor, the occupant sensor, and the wireless RFcommunication module; wherein the central control system comprises: awireless RF communication module for wirelessly communicating with theplurality of remote wireless sensor nodes; and a controller configuredto use a priority schedule to prioritize temperature control among theplurality of areas of the structure.
 2. The multi-nodal thermostatsystem for the structure of claim 1, wherein the central control systemcomprises a thermostat that: receives user input indicative of a desiredtemperature, controls the HVAC system based on the desired temperature,and wirelessly communicates with the plurality of remote wireless sensornodes.
 3. The multi-nodal thermostat system for the structure of claim1, wherein the controller of the central control system is configured tocontrol the HVAC system of the structure to bring one or moreprioritized areas of the plurality of areas of the structure to adesired temperature based on the priority schedule.
 4. The multi-nodalthermostat system for the structure of claim 1, wherein the controllerof the central control system is configured to receive a priorityschedule provided by a user.
 5. The multi-nodal thermostat system forthe structure of claim 1, wherein the priority schedule used by thecontroller of the central control system to prioritize temperaturecontrol among the plurality of areas of the structure is based at leastin part on occupancy sensing performed by the plurality of remotewireless sensor nodes.
 6. The multi-nodal thermostat system for thestructure of claim 1, wherein the priority schedule used to prioritizetemperature control among the plurality of areas of the structure isdetermined by the controller of the central control system at leastpartially based on a time of day.
 7. The multi-nodal thermostat systemfor the structure of claim 6, wherein the priority schedule used toprioritize temperature control among the plurality of areas of thestructure is additionally determined by the controller of the centralcontrol system at least partially based on occupancy data received fromthe plurality of remote wireless sensor nodes.
 8. The multi-nodalthermostat system for the structure of claim 1, wherein the centralcontrol system further comprises a display in communication with thecontroller of the central control system such that the controller cancause a current temperature at a remote wireless sensor node of theplurality of the remote wireless sensor nodes to be displayed by thedisplay.
 9. The multi-nodal thermostat system for the structure of claim1, wherein the occupant sensor of each remote wireless sensor node ofthe plurality of the remote wireless sensor nodes is selected from thegroup consisting of: an infrared sensor, a motion sensor, and anultrasonic sensor.
 10. The multi-nodal thermostat system for thestructure of claim 2, wherein the thermostat comprises a visual displaythat presents a current temperature and a setpoint temperature.
 11. Themulti-nodal thermostat system for the structure of claim 1, wherein thecontroller of the central control system combines a subset of multipleremote wireless sensor nodes of the plurality of the remote wirelesssensor such that a composite area is defined for the priority scheduleto prioritize temperature control among the plurality of areas of thestructure.
 12. The multi-nodal thermostat system for the structure ofclaim 1, wherein the central control system is configured to receive amodification to the priority schedule via the Internet.
 13. Themulti-nodal thermostat system for the structure of claim 1, wherein eachremote wireless sensor node of the plurality of the remote wirelesssensor nodes enters a sleep state for a period of time betweenmeasurements by the temperature sensor and the occupant sensor, thesleep state requiring less power from the power source than a non-sleepstate.
 14. The multi-nodal thermostat system for the structure of claim1, wherein the central system transmits a wake-up signal to each remotewireless sensor node of the plurality of the remote wireless sensornodes via the wireless RF communication module of the central controlsystem.
 15. The multi-nodal thermostat system for the structure of claim1, wherein each remote wireless sensor node of the plurality of theremote wireless sensor nodes in response to the wake-up command,performs a measurement by the temperature sensor and transmits themeasurement to the central control system.
 16. The multi-nodalthermostat system for the structure of claim 1, wherein each remotewireless sensor node of the plurality of the remote wireless sensornodes stores an identifier specific to the remote wireless sensor nodeand the identifier is included in each data packet transmitted by thewireless RF communication module of the remote wireless sensor node. 17.The multi-nodal thermostat system for the structure of claim 1, whereinthe power source of each remote wireless sensor node of the plurality ofthe remote wireless sensor nodes comprises a battery and the remotewireless sensor node is configured to transmit a battery health messageto the central control system via the wireless RF communication module.18. The multi-nodal thermostat system for the structure of claim 1,wherein the wireless RF communication module of each remote wirelesssensor node of the plurality of the remote wireless sensor nodesperforms frequency hopping and communicates with the central controlsystem on various frequency bands around 900 MHz.
 19. The multi-nodalthermostat system for the structure of claim 1, wherein each remotewireless sensor node of the plurality of the remote wireless sensornodes comprises an electronically-controlled register vent (ECRV) thatcan be actuated open or shut in response to a command from the centralcontrol system to help the area of the structure corresponding to theremote wireless sensor node reach a temperature matching a setpointtemperature indicated by a user.
 20. The multi-nodal thermostat systemfor the structure of claim 1, wherein the controller of the centralcontrol system is configured to control the HVAC system of the structureto bring one or more prioritized areas of the structure to a desiredtemperature based on the priority schedule.